Paging in a wireless network

ABSTRACT

A network node determines a paging occasion of a user equipment (UE). In response to a received paging message, the network node transmits on a control channel in the determined paging occasion a signal including an indication of shared channel resources. The signal may be derived from a radio network temporary identifier (RNTI).

CROSS REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.14/222,140, filed Mar. 21, 2014, which is a continuation of U.S. patentapplication Ser. No. 11/416,865, filed May 2, 2006, which issued as U.S.Pat. No. 8,682,357 on Mar. 25, 2014, which are incorporated by referenceas if fully set forth.

BACKGROUND OF THE INVENTION

Field of the Invention

The invention generally relates to wireless communication systems, andmore particularly, to establishing connectivity in a cellularcommunication system.

Description of the Related Art

Wireless communication systems support a sleep mode to minimize batterypower consumption of user equipment (UE), such as a mobile terminal. Insleep mode, the mobile terminal performs little or no activity, and doesnot transmit/receive traffic data. Therefore, the mobile terminal insleep mode only consumes a small amount of radio link resources, if any.Consequently, a large number of users can simultaneously be supported inthe system.

A mobile terminal can terminate sleep mode and connect to a Radio AccessNetwork (RAN) of base stations (otherwise known as “Node B”s accordingto the 3GPP protocol) in two ways. If traffic needs to be transmittedfrom the mobile terminal, the mobile terminal may terminate the sleepmode by requesting a connection to the network. This is denoted a“mobile terminal initiated (originated) connection.” Otherwise, thenetwork may request the mobile terminal to make a connection to thenetwork. This is denoted a “network-initiated connection”. The procedureused for waking up the mobile terminal from the sleep mode in“network-initiated connection” employs paging.

Paging involves waking up the mobile terminal from the sleep state.After waking up, the mobile terminal reads the paging message(s)transmitted in a downlink paging channel(s). The mobile terminal eitherconnects to the network or performs the task instructed by the networkvia the paging message(s).

Depending on the amount of activity and connectivity involved, the sleepmode can be categorized into two sub-modes as “idle (standby)” and“dormant”. In idle mode, the mobile terminal has no connection to theRAN; however, it is connected to the core network. In contrast, in thedormant state the mobile terminal is connected to the RAN. In order toassist mobility in sleep mode, the mobile terminal is registered in aregistration area or “paging zone”. The mobile terminal informs thenetwork of its location and status in the registration process. Thisenables efficient paging in case of network-initiated connectionestablishment. A registration area may be defined as a zone (e.g., oneor more cells) respectively controlled by a base station (or Node-B) ora plurality of base stations (or Node-Bs). A registration area may bealso be known as a “routing area”, “tracking area”, “location area”, or,for Universal Mobile Telecommunications Systems (UMTS) implementing 3Gwireless communications, “UTRAN registration area (URA)”.

The mobile terminal performs a registration whenever the “registrationarea” is changed. In other words, whenever the cell the mobile terminalis camped on broadcasts a “registration area” identity which isdifferent from the registration area that the mobile terminal previouslyregistered, then the mobile terminal should perform a registrationupdate. Here, it is assumed each cell broadcasts only one “registrationarea” identity. However, the registration area may be defined to includeoverlapping zones. In that case, the cell would broadcast multipleregistration area IDs.

In the conventional paging procedure, two signals are used to convey thepaging message. The first paging signal is used to indicate whether apaging message is being transmitted to a particular UE or group of UEs.The second paging signal carries the paging message(s) for theparticular UE or group of UEs. The second paging signal is transmittedfollowing the first paging signal at a fixed time offset from the firstpaging signal.

The mobile terminal uses Discontinuous Reception (DRX) in sleep mode inorder to reduce power consumption. When DRX is used, the mobile terminalneeds to monitor the first paging signal only at one paging occasion perDRX cycle. The length of the DRX cycle is core network domain specificand may be updated locally in the mobile terminal using informationgiven in system information from the core network.

The core network usually knows when the mobile terminal will bemonitoring the first paging signal within DRX cycle. Thus, if thenetwork intends to page a particular mobile terminal, it sends the firstpaging signal at the time when the mobile terminal will monitor thepaging channel. If the mobile terminal does not receive any paging inthe first paging signal, it goes back to the sleep mode. Otherwise, themobile terminal reads the second paging signal.

The network may page the mobile terminal to establish a networkoriginated call or to trigger reading of updated system information. Inresponse to the paging message, the mobile may establish a connectionwith the RAN (if the mobile terminal is in an “idle” state), or updatethe mobile terminal location using a cell update procedure (if themobile terminal is in a “dormant” state).

Upon receipt of the paging response, the RAN knows the location of themobile terminal at the cell level. Thus, the radio resources canefficiently be allocated to the mobile terminal for the call.

In the conventional system, the connection establishment and cell updateresponse to a paging message (network-initiated connection) follow thesame procedures as when the connection establishment/cell update isperformed in response to a “terminal initiated connection”. In thelatter case, the establishment cause is not known to the network until aconnection request message is received by the mobile terminal.Therefore, the network can manage the connection setup only afterreceiving the initial connection request from the mobile terminal.

BRIEF SUMMARY OF THE INVENTION

In the case of a network-initiated connection, before the network pagesthe mobile terminal it knows the cause for connection establishment, andalso the terminal context, to some extent, because the terminal isconnected to the core network even when it is in the idle state.Therefore, the information known at the network may be used to optimize(speed up) connection establishment between the mobile terminal and theRAN.

Embodiments of the present invention provide a network-initiatedconnection establishment procedure which uses the information known atthe network to speed up the connection between the mobile terminal andRAN. The invention uses a paging procedure to inform the mobile terminalof a network-initiated connection. The paging message is designed tosupport fast connection establishment over a shared channel.

Embodiments of the present invention provide a method of establishing anetwork-initiated connection between a mobile terminal User Equipment(UE) and a Radio Access Network (RAN) in which (1) the network (e.g., anaGW) initiates the connection by transmitting a paging message to theNode Bs in the UE registered tracking area, and (2) the Node Bs(belonging to the tracking area) receive the paging message and affixthe paging message with a cell-specific radio network temporary identity(c-RNTI) and index(es) to one or a set of shared control channels(SCCHs). The c-RNTI and SCCHs are selected from the available c-RNTIsand SCCHs for the cell. The selection of c-RNTI and SCCH may be managedby the scheduler at the Node B, the core network (e.g., the aGW), or aseparate radio resource manager (RRM) server.

The complete message is broadcast in the cell. The recipient UE may usethe c-RNTI as a temporary cell-specific identity, and the SCCH as theassociated shared control channel for shared channel operation. If themessage is intended for the UE then it sends a paging acknowledgementmessage in the uplink. The message may be sent over a contention-baseduplink channel (e.g. RACH) or a dedicated physical channel.

Upon the network's receipt of the paging acknowledgment from the UE, ashared channel connection is established between the UE and the network.After establishment of the shared channel connection, signalling andtraffic data is transmitted over scheduled shared channel resources.

The paging message may be conveyed to the UE using: (1) pagingindicators mapped onto a paging indicator channel (PICH), and the pagingmessage mapped onto separate paging channels (PCH), (2) pagingindicators mapped onto a shared control channel (SCCH) and the pagingmessage mapped onto separate paging channels (PCH); or (3) pagingindicators mapped onto a shared control channel (SCCH) and the pagingmessage mapped onto a downlink shared transport channel (SCH).

The paging acknowledgment message may be transmitted along with anuplink (UL) synchronization message over a contention-based randomaccess channel, or as a separate paging acknowledgment message over sucha channel.

The selection of c-RNTI and SCCH (to be attached to the paging message)may be managed by the Node B. The Node B selects an unused c-RNTI andone or a set of SCCHs, and signals these to the UE with the pagingmessage. The paging message broadcast in different cells may havedifferent c-RNTIs and SCCHs.

Alternatively, the selection of c-RNTI and SCCH may be managed by theaGW or a separate RRM server, in which case the c-RNTI and SCCH may beselected as cell-specific so that each Node B sends a paging messageusing different c-RNTIs and SCCHs. The c-RNTI and SCCH may alternativelybe tracking-area specific, so that each Node B in the tracking areasends paging messages including the same c-RNTI and SCCH.

BRIEF DESCRIPTION OF THE DRAWING(S)

FIG. 1 illustrates an example of a cellular communication systemaccording to embodiments of the invention.

FIG. 2 illustrates network-initiated connection establishment accordingto embodiments of the invention.

FIG. 3 illustrates an example of signaling flow according to embodimentsof the invention.

FIG. 4 illustrates the format of a paging signal broadcast in a cellaccording to embodiments of the invention.

FIG. 5 illustrates the format of a paging signal broadcast in a cellaccording to embodiments of the invention where dedicated accessresources are signalled to the UE.

FIG. 6 illustrates resources available for allocation according toembodiments of the invention.

FIGS. 7-9 illustrate three different ways in which a paging message maybe mapped according to embodiments of the invention.

FIG. 10 illustrates the format of a paging acknowledgement includinguplink synchronization according to embodiments of the invention.

FIG. 11 illustrates the paging messages broadcast in different cellshaving different c-RNTIs and SCCHs, according to embodiments of theinvention.

FIG. 12 illustrates the paging messages broadcast in different cellhaving the same c-RNTI and SCCH in all cells within a tracking area,according to embodiments of the invention.

FIG. 13 illustrates signalling flow in idle mode according toembodiments of the invention.

FIG. 14 illustrates a flow diagram according to embodiments of theinvention.

FIG. 15 illustrates a flow diagram according to embodiments of theinvention.

FIG. 16 illustrates a flow diagram according to embodiments of theinvention.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the invention enable the RAN to perform network-initiated(originated) connection establishment over shared transport channels(SCHs). The SCHs are associated with a set of physical Shared ControlChannels (SCCHs). Specific information required by the UE for correcttransmission/reception over the SCHs is conveyed from RAN to UE over theSCCHs. For downlink, this information may specify the resources to beused for the downlink transmission, and information regarding theformatting of the data to enable its correct reception at the UE. Forthe uplink, the information might again specify which transmissionresources are to be used along with other shared channel grantinformation (power allocation, etc.). In both cases, the terminal towhich the shared channel grant is directed is identified on the sharedchannel based on a RAN (or cell) Specific Temporary Identification(c-RNTI), which is signalled to the UE by the RAN within the SCCHitself.

FIG. 1 illustrates an example of a cellular communication systemaccording to embodiments of the invention. The network includes a userequipment (UE) domain, a radio access network (RAN) domain, and a corenetwork domain. The UE domain includes user equipment 110 thatcommunicate with at least one base station 112 in the RAN domain via awireless interface. The RAN domain may also include a network controller(e.g., radio network controller) (not shown), such as that used in UMTSsystems. Alternatively, such functionality may be distributed betweenthe Node Bs and the aGW or other controller in the core network. FIG. 1also illustrates an optional radio resource manager (RRM) 114. Asdescribed below, the RRM may perform functions otherwise performed bythe Node Bs or aGW in some embodiments.

The core network (CN) 116 includes, in this example, an access gateway(aGW) 118, a serving GPRS support node (SGSN) 120, and a gateway GPRSsupport node (GGSN) 122. The core network is coupled to an externalnetwork 124. The SGSN 120 is responsible for session control, includingkeeping track of the location of the UEs. The GGSN 122 concentrates andtunnels user data within the core network 116 to the ultimatedestination (e.g., an Internet service provider) in the external network124. Further details may be found in the 3GPP UMTS technicalspecifications, such as TS 23.246 v6.4.0 “3rd Generation PartnershipProject; Technical Specification Group Services and System Aspects;Multimedia Broadcast/Multicast Service (MBMS); Architecture andFunctional Description (Release 6),” published by the 3GPP SupportOffice, 650 Route des Lucioles—Sophia Antipolis, Valbonne—FRANCE, whichare incorporated by reference herein.

FIG. 2 illustrates network-initiated connection establishment accordingto embodiments of the invention. A network controller (e.g., an accessgateway 118 in a core network) sends a paging message to the Node Bs 112in the registration area to be broadcast in the cells. Before the pagingmessage is broadcast in each cell, the Node B attaches a c-RNTI and SCCHindex to the message. The c-RNTI and SCCH is selected from the availablec-RNTIs and SCCHs in the cell and may, in some embodiments, be managedby a scheduler at the Node B. The corresponding UE 110 (the UE to whichpaging is indicated) uses this c-RNTI and SCCH index for datatransmission over shared channels.

FIG. 3 illustrates an example of signaling flow in an embodiment of thenetwork-initiated connection establishment procedure. The network sendsa paging message to the UE 110 via the Node Bs 112 to initiate aconnection. First, the core network (or, more particularly in someembodiments, access gateway 118 within the core network) transmits thepaging message to the relevant Node Bs in the registration area. Afterreceiving the paging message from the core network, each Node B selectsa c-RNTI and SCCH index (in one embodiment), and forms the paging signalto be broadcast in the corresponding cell. Thus the paging signalbroadcast in the cell includes the paging message (cause, UE identity)from the core network, c-RNTI and the SCCH index (see FIG. 4). The UEidentity may be expressed by the international mobile subscriberidentity (IMSI) or temporary mobile subscriber identity (TMSI), whichare known in the 3G standard. The recipient UE may use this c-RNTI asthe cell-specific identity and the SCCH as the associated shared controlchannel for the shared channel operation.

After decoding the paging message, the UE sends a paging acknowledgementmessage to the Node Bs in the RAN. The message may be combined withuplink synchronisation information and transmitted over acontention-based uplink channel (such as a random access channel(RACH)).

Due to possible UE collision on the contention-based uplink channel, thepaging acknowledgement message may experience some delay. This can beavoided by allocating dedicated physical access resources for thetransmission of the paging response message. If this is used, then theallocated physical access resources for the uplink transmission (pagingresponse) may be signalled to the UE together with the paging message.Thus the paging signal may take the format shown in FIG. 5.

The dedicated access resources may be a subset of resources allocatedfor access channels (see FIG. 6). However, these resources may bereserved for allocation by the network, in contrast to selection by theUE in a normal contention-based RACH operation. The same message formatis used for both the RACH channel and the dedicated access channel. Theinformation on random access resources (RACH channels) is broadcast overa broadcast control channel (BCCH), whereas the channel information forthe dedicated access channels is not broadcast in the cell. Thisinformation is transmitted to the UE together with the paging signalaccording to one embodiment of the invention.

Upon receipt of the paging acknowledgment from the UE, a shared channelconnection is established between the RAN and the UE, and signalling andtraffic data will be transmitted over scheduled shared channelresources.

Mapping of Paging Message

In some embodiments, two-stage paging is employed. Referring to FIGS.7-9, paging signal 1 wakes up a group of UEs to read the pagingmessage(s), which are transmitted in paging signal 2. Three differentimplementations of two-stage paging are described herein.

Implementation 1

A paging signal 1 is mapped onto a separate physical channel, such as apaging indicator channel (PICH). A group of UEs wake up and read thePICH channel at a paging occasion calculated based on the DRX cycle andIMSI (used herein as an example of a UE identifier known by the corenetwork). If a paging indicator is set to true, the UEs corresponding tothe paging indicator read the paging message transmitted in pagingsignal 2.

The paging signal 2 may be mapped to separate paging channels (PCH).From the IMSI, the UE may calculate which paging channel to read, andread the paging message within the paging channel carrying the UE'sIMSI. The system may use one PICH and a set of PCHs to enable paging formultiple UEs at a given paging occasion (see FIG. 7).

Implementation 2

In another embodiment, the paging signal 1 may be mapped onto SCCH. Inthis case a group ID or an ID specified for paging (paging ID) can beused in an ID field of SCCH. The paging indicators may be mapped to anSCCH information field (FIG. 8). Note that the channel format of SCCH(used for paging signal 1) is different from that used in the “normal”shared channel operation.

The paging signal 2 is transmitted over the paging channel (PCH). Inthis case, the UEs wake up from sleep mode as defined by the DRX cycleand IMSI, and read the SCCH for paging indicators. The location of apaging indicator within a paging signal 1 may be calculated based on theIMSI. If only one SCCH is used for paging indicators, a predefinedpaging ID may be used to inform the UE that paging signal 1 is a pagingindicator-specific message. Otherwise, several SCCH may be used.

The UE corresponding to the same paging occasion may be assigned to agroup, and each group is assigned a group ID. The user group ID may belocated in the identity field in SCCH. The UEs belonging to the usergroup defined by the user group ID read the SCCH corresponding to theUEs' user group for their paging indicators. If the corresponding pagingindicator is set to true, then the UE reads the paging signal 2, whichis transmitted over the PCH and defined by the UE's IMSI. From the IMSI,the UE calculates which paging channel to read, and reads the pagingmessage within the paging channel carrying the UE's IMSI. The system mayuse one or a set of SCCHs and one or a set of PCHs to enable paging formultiple UEs at a given paging occasion.

Implementation 3

This implementation uses SCCH and SCH to transmit paging signals. Inaddition, the same channel format as used in the normal shared channeloperation is employed. Each UE learns which SCCH to monitor based uponeither system information broadcast to the UEs, or because the SCCHindex is preprogrammed in the UE pursuant to the applicable standard.The UEs listen to the appropriate SCCH for paging indicators at theirpaging occasion calculated based on DRX cycle and IMSI. The UEs with thesame paging occasion are divided into groups based on the IMSI. Eachgroup is given a user group ID, as indicated in the SCCH ID field. Themessage part of SCCH indicates the resources allocated for acorresponding SCH channel, which carries the paging message(s) (pagingsignal 2). If the UE belongs to the user group indicated in the SCCH IDfield, the UE reads the allocated SCH for its paging message. An exampleimplementation is shown in FIG. 9. The system may use a set ofSCCHs/SCHs to enable paging for multiple UEs at a given paging occasion.

Paging Acknowledgement/UL Synchronisation

After receiving the paging message from the network, the UE sends apaging acknowledgment message in the uplink (UL). The message may besent over a contention-based channel (such as a random access channel(RACH)) or an allocated, dedicated access channel.

The paging acknowledgement may be sent separately or combined with a ULsynchronisation request message. If the paging acknowledgment iscombined with the UL synchronisation request message, the message maycontain c-RNTI, which is signalled in the paging message, and asignature sequence which is selected from a set of sequences broadcastin a broadcast channel (BCH), or specified in the applicablecommunication standard specification (to be used for ULsynchronisation), which may be programmed into the UE. The messageformat is shown in FIG. 10.

In another embodiment, the UE may send the paging acknowledgment and ULsynchronisation in separate messages, in which case the pagingacknowledgment message only contains the c-RNTI value signalled in thepaging message. This may be sent over RACH or over an allocated,dedicated access channel.

After receiving the paging acknowledgment from the UE, the Node B knowsthe UE location at the cell level. The Node B then establishes a radioconnection between the UE and the Node B over a shared channel. The UEuses the c-RNTI and the SCCH index, which are signalled with the pagingmessage to identify the UE and the SCCH, respectively, during sharedchannel operations. The Node B conveys the paging acknowledgment fromthe UE to the Core network. This completes the connection between the UEand the network.

SCCH and c-RNTI Management

One way to manage the allocation of c-RNTI and SCCH is to allow the NodeBs to select c-RNTIs and SCCHs. After receiving a paging request fromthe aGW, the Node B may select an unused c-RNTI and one or a set ofSCCHs to be used by the UE, if, e.g., the UE is in the idle state.During idle mode, the UE is not connected to a Node B, but is connectedto the core network. The UE is known by its UE identifier (e.g., IMSI orTMSI) at the core network. In some embodiments, the Node B provides atemporary ID to the UE to connect the UE and the base station. After theNode B receives a paging acknowledgement from the UE, the Node B sendsthe paging acknowledgement to the core network to complete the binding,enabling the core network to know that the UE is within the coveragearea of the Node B.

If the paged UE has already been assigned a c-RNTI and a set of SCCHs bythe Node B (e.g., the case when the UE is in dormant state), thepreviously assigned c-RNTI and SCCHs may be used within the pagingsignal by the Node B. This results in the paging messages broadcast indifferent cells having different c-RNTIs and SCCHs, as shown in FIG. 11.

Alternatively, the c-RNTI and SCCH may be managed/selected by the aGW inthe core network or a separate RRM server. C-RNTI and SCCH may beselected as cell-specific, in which case each Node B sends a pagingmessage including different c-RNTIs and SCCHs affixed to the sameinitial paging message from the core network or RRM. Alternatively, thepaging message may be sent including the same c-RNTI and SCCH in allcells within a tracking area (FIG. 12). In that case, the aGW or RRM mayreserve a set of c-RNTIs and SCCHs for use in paging requests.

When the RRM is employed, it takes over the function of assigning c-RNTIand SCCHs. (The aGW, in one embodiment, still sends the paging message.)The RRM server reserves a set of temporary identifiers and SCCHs. TheRRM selects, allocates and keeps track of the assignment of temporaryidentifiers and SCCHs to paging messages. The RRM does not need to knowthe UE identifier (e.g., IMSI or TMSI).

Network-initiated connection establishment may vary depending on the UEconnection states (e.g., idle or dormant states) and the paging cause.

Paging for Idle State UEs

Idle state UEs are not known at the cell level because they aregenerally not connected to the RAN. Therefore, the UE would not have ac-RNTI or SCCH specified for its use in shared channel operation.However, the level of connection to the network may have twodefinitions. In one definition, the UE has no connection to the RAN, butit is connected to the core network. The network does not store UEcapability or security information regarding Idle mode UEs (this is thedefinition used for idle mode in conventional systems).

According to the second definition of the idle state, the UE isconnected to the core network and has limited connection to the RAN.With this limited connection, however, the UE does not have c-RNTI, SCCHor radio resources allocated. Nevertheless, the UE is registered withinthe network, in which case the network would have a UE context (such asUE capabilities) stored in the network. Also, the security mode controland authentication procedures have been performed during the UEregistration, and the security keys (ciphering, integrity protection)may have been exchanged between the network and the UE. The securitykeys would be stored in the UE and the network. (This is a possibledefinition of the idle state that may be used in LTE, i.e., the“long-term evolution” or next generation of the communications standardafter UMTS.)

According to the two definitions for idle mode, two alternativenetwork-initiated connection establishment procedures may beimplemented.

FIG. 13 depicts the signalling flow involved in network-initiatedconnection establishment in the case for an Idle mode UE with limitedconnection to the RAN (possible Idle state definition in LTE).

The paging message indicates with a UE identifier, such as IMSI, whichUE has been paged. The paging message may be ciphered and sent (from aGWor other core network element) transparent to the Node B. Paging isbroadcast in the cell (by Node Bs) according to the paging proceduredescribed with respect to FIG. 3. After receiving the paging message,the UE sends a paging acknowledgment (with or without UL synchronisationrequest). The Node B conveys the paging acknowledgment to the aGW. Notethat security control or authentication is not necessary as theauthentication has already been performed and the security informationis stored in the aGW.

When the paging acknowledgment is received by the network, theconnection is established between the UE and the network for sharedchannel operation. The c-RNTI and SCCH index signalled with the pagingmessage is used by the UE as the shared channel IDs.

After sending the paging acknowledgment message, the UE listens to theallocated SCCH (which is signalled with the paging message) for resourceallocation on SCH. The aGW issues a Radio Access Bearer (RAB) assignmentrequest to the Node B. The Node B assigns radio resources for themessage transmission, and the UE is informed about the allocatedresources over SCCH. The timing advance information calculated at theNode B for uplink time synchronisation may also be mapped on to theSCCH. The timing advance information may alternatively be conveyed usinga separate physical channel. [Node B computes propagation delay andsignals back timing advance information to UE, so that signals from allUEs will be time synchronized at the Node B.]

The Node B sends a radio bearer setup message using the allocatedphysical resources on DL-SCH (downlink shared channel). The radio bearersetup complete message is sent on UL-SCH (uplink shared channel). Uponreceipt of RAB assignment response by the aGW, the data transmission iscommenced over the shared channel.

The radio bearer setup/response message may be sent using a logicaldedicated control channel (DCCH) mapped onto a shared transport channel(SCH). In that case, a default bearer configuration is used for themessage (radio bearer setup/response message) transmission.

In some embodiments, the system may employ a default (or stored) radiobearer configuration (or some part of that configuration) for the datatransmission. In this case, the use of default (or stored) configurationinformation may be signalled within the paging message. If so, only theadditional information needed in the case of a radio bearerre-configuration needs to be communicated between the RAN and UE beforethe data transmission is commenced.

If no UE security or authentication information is kept in the networkin the idle state, the security control and authentication may beperformed before the radio bearer configuration step. The securitycontrol may also be performed over SCH using the allocated c-RNTI as theUE identification over SCH. The resource allocation is communicated overthe allocated SCCH.

Paging for Dormant State UEs

In the dormant state, the UE is connected to the network. Thus, it isgiven a c-RNTI from the Node B with which the UE was last registered.The UE may have gone out of the coverage area of the Node B. Thus the UEis paged in the cells (Node Bs) belonging to the tracking area.

The paging for dormant state UEs is similar to that for idle state UEsdescribed above. However, as the UE has already allocated a c-RNTI, thesame c-RNTI may be used with the paging message when the UE is paged inthe cell with which it was last registered.

In accordance with the foregoing teachings, and referring to FIG. 14, abase station can be configured to receive (201) a network-initiatedconnection establishing message associated with a unique identifier ofthe user equipment and an allocation of dedicated physical accessresource for the user equipment, send (202) the network-initiatedconnection establishing message together with a temporary identifier andan indication of an allocation of dedicated physical access resource forthe user equipment, the temporary identifier being different from theunique identifier, receive (203) an acknowledgement response to thenetwork-initiated connection establishing message from the userequipment wherein the acknowledgement response is received using thededicated physical access resource for the user equipment, and inresponse to the acknowledgement response, establish (204) a sharedchannel connection between the base station and the user equipment,wherein the temporary identifier identifies the user equipment on theshared channel.

Similarly, and referring to FIG. 15, a resource manager can beconfigured to select (301) a temporary identifier for the user equipmentand then provide (302) the temporary identifier to a base station fortransmission by the base station to the user equipment along with anetwork-initiated connection establishing message, the network-initiatedconnection establishing message conveying a unique identifier of theuser equipment that is different from the temporary identifier and anallocation of dedicated physical access resource for the user equipment,the temporary identifier for identifying the user equipment duringshared channel operation between the user equipment and the basestation.

And as a further illustrative example in these regards, and referringnow to FIG. 16, a user equipment can be configured to receive (401) froma base station a network-initiated connection establishing messageconveying a unique identifier of the user equipment, a temporaryidentifier which is different from the unique identifier, and anindication of an allocation of dedicated physical resource for the userequipment and then send (402) an acknowledgement response to thenetwork-initiated connection establishing message to the base stationusing the allocation of dedicated physical access resource for the userequipment to establish a shared channel connection between the basestation and the user equipment, wherein the temporary identifieridentifies the user equipment on the shared channel.

While the invention has been described in terms of particularembodiments and illustrative figures, those of ordinary skill in the artwill recognize that the invention is not limited to the embodiments orfigures described. Although embodiments of the present invention aredescribed, in some instances, using UMTS terminology, those skilled inthe art will recognize that such terms are also used in a generic senseherein, and that the present invention is not limited to UMTS or 3Gsystems.

Those skilled in the art will recognize that the operations of thevarious embodiments may be implemented using hardware, software,firmware, or combinations thereof, as appropriate. For example, someprocesses can be carried out using digital circuitry or processors underthe control of software, firmware, or hard-wired logic. (The term“logic” herein refers to fixed hardware, programmable logic and/or anappropriate combination thereof, as would be recognized by one skilledin the art to carry out the recited functions.) Software and firmwarecan be stored on computer-readable media. Some other processes can beimplemented using analog circuitry, as is well known to one of ordinaryskill in the art.

It will be appreciated that, for clarity purposes, the above descriptionhas described embodiments of the invention with reference to differentfunctional units and processors. However, it will be apparent that anysuitable distribution of functionality between different functionalunits, processors or domains may be used without detracting from theinvention. For example, functionality illustrated to be performed byseparate processors or controllers may be performed by the sameprocessor or controller. Hence, references to specific functional unitsare only to be seen as references to suitable means for providing thedescribed functionality, rather than indicative of a strict logical orphysical structure or organization.

Although the present invention has been described in connection withsome embodiments, it is not intended to be limited to the specific formset forth herein. Rather, the scope of the present invention is limitedonly by the claims Additionally, although a feature may appear to bedescribed in connection with particular embodiments, one skilled in theart would recognize that various features of the described embodimentsmay be combined in accordance with the invention.

Furthermore, although individually listed, a plurality of means,elements or method steps may be implemented by, for example, a singleunit or processor. Additionally, although individual features may beincluded in different claims, these may possibly be advantageouslycombined, and the inclusion in different claims does not imply that acombination of features is not feasible and/or advantageous. Also, theinclusion of a feature in one category of claims does not imply alimitation to this category, but rather the feature may be equallyapplicable to other claim categories, as appropriate.

What is claimed is:
 1. A network node comprising: an interface, the interface configured to receive from a core network a paging message for a user equipment (UE); and a processor communicatively coupled to the interface, the processor configured to determine a paging occasion of the UE responsive to the received paging message, to facilitate transmission to the UE on a control channel during the paging occasion, a first signal including an indication of shared channel resources, the first signal being derived from a radio network temporary identifier (RNTI), and to facilitate transmission, on the indicated shared channel resources, a second signal to the UE.
 2. The network node of claim 1, wherein the paging occasion is derived from an International Mobile Subscriber Identity (IMSI) of the UE.
 3. The network node of claim 1, wherein the RNTI is associated with a plurality of UEs.
 4. The network node of claim 1 further comprising receiving circuitry further configured to receive a random access channel (RACH) transmission from the UE based on the transmitted second signal on the indicated shared channel resources.
 5. The network node of claim 4, wherein the processor is further configured to transmit information over a shared channel to the UE based on the received RACH transmission.
 6. The network node of claim 1, wherein the second signal transmitted on the indicated shared channel resources includes a paging message.
 7. The network node of claim 1, wherein the processor is further configured to determine the paging occasion using a discontinuous reception (DRX) cycle of the UE.
 8. A method performed by a network node, the method comprising: receiving, by the network node from a core network, a paging message for a user equipment (UE); and determining, by the network node, a paging occasion of the UE responsive to the received paging message, transmitting, by the network node to the UE on a control channel during the paging occasion, a first signal including an indication of shared channel resources, the first signal being derived from a radio network temporary identifier (RNTI), and transmitting, by the network node on the indicated shared channel resources, a second signal to the UE.
 9. The method of claim 8, wherein the paging occasion is derived from an International Mobile Subscriber Identity (IMSI) of the UE.
 10. The method of claim 8, wherein the RNTI is associated with a plurality of UEs.
 11. The method of claim 8 further comprising: receiving, by the network node, a random access channel (RACH) transmission from the UE based on the transmitted second signal on the indicated shared channel resources.
 12. The method of claim 11, wherein the network node transmits information over a shared channel to the UE based on the received RACH transmission.
 13. The method of claim 8, wherein the second signal transmitted on the indicated shared channel resources includes a paging message.
 14. The method of claim 8, wherein the network node determines the paging occasion using a discontinuous reception (DRX) cycle of the UE. 